1. Field of the Invention
The present invention generally relates to dishwashers, and more particularly, to controlling the operation of a water pump or a water heater of a dishwasher.
2. Background of the Invention
Water pumps and water heaters are commonly used in dishwashers in order to increase the pressure and temperature, respectively, of the water used in the dishwasher. The water pump increases the water pressure before the water is sprayed on the dishes, thereby improving the cleaning effectiveness of the water. The water heater raises the temperature of the water before the water is sprayed on the dishes, which also improves the cleaning effectiveness of the water and dissolved detergent.
Both water pumps and water heaters in dishwashers rely on the presence of water in order to operate properly. In the absence of water, water pumps and water heaters can overheat, resulting in damage or destruction to the water pumps and water heaters and/or other components of the dishwasher. Moreover, a “dry” water heater poses a fire hazard. During normal operation of the dishwasher this is not a problem because the dishwasher supplies the water heater and water pump with water on which to operate. The dishwasher automatically opens at least one valve, thereby allowing water to enter the dishwasher, before the dishwasher applies power to either the water pump or the water heater. Thus, water is normally present when the water pump and the water heater are operated.
A problem does arise, however, if water does not enter the dishwasher as intended when the valve is opened. Water may not be available, for instance, if there is a leak in the valve, a leak in the pipes leading to the valve, or a failure of the water supply such as if the main water valve leading to the dishwasher valve is closed. In this event, the dishwasher may apply power to the water pump and/or the water heater on the assumption that water is present in the dishwasher. Because no water is, in fact, present, the water heater and/or the water pump may overheat and cause damage to themselves and/or to other parts of the dishwasher.
Accordingly, there is a need for a dishwasher that, among other things, (1) prevents the water pump and water heater from operating if water is not available; and (2) notifies the user of the unavailability of the water. The present invention addresses these and other needs.